Structural–chemical features and mechanism of crystallization of TlAsX2 glasses (X = S, Se)

Resumo

The vibrational IR spectra of polymer-chain glasses and single crystals of TlAsX₂ (X = S, Se) have been studied. The results of the kinetic study of the surface isothermal crystallization of glasses are theoretically anlayzed in different ways, taking into account the peculiarities of their structure. The semiempirical calculation of the temperature dependence of nonreconstructive crystal growth rate is performed. It is shown that the layered stationary growth of crystals in the TlAsS₂ glass occurs on screw dislocations. In the TlAsSe₂ glass the transition from a dislocation mechanism to two-dimensional nucleation and the layered growth of crystals is possible at supercooling of more than 120°C.